Apparatus for making cellular glass blocks



Sept. 30, 1941. H 2,257,681 APPARATUS-FOR MAKING CELLULAR'GLASS BLOCKSFiled Jan. 28, 1938 5 Sheets-Sheet l nvmvmn 2. Mse h. HF7U I TTORNEYS.

E. H. HAUX Se t. 30, 1941..

APPARATUS FOR MAKING CELLULAR GLASS BLOCKS 5 Sheets-Sheet 2 Filed Jan.28, 1938 f 1. nae/i HHUA/ 7 RNEYS.

Sept. 30, 1941. E. H..HAUX' I 2,257,681

APPARATUS FOR MAKING CELLULAR GLASS BLOCKS Filed Jan. 28, 1938 5 e h et5 6 TTORNEYS.

Sept. 30, 1941. E. H. HAUX 2,257,631

APPARATUS FOR MAKING CELLULAR GLASS BLOCKS.

Filed Jan. 28, 1938 5 Sheets-Sheet 4 INVENTUR. fZMEE f-l. Hnu

p 0, 1 4 E. H. HAUX A 2,257,681

APPARATUS FOR MAKING CELLULAR GLASS BLOCKS Filed Jan. 28, 1938 5shets-sheet s I r I 1 a1 fis 7 7s Z .729. 2' 55 74 INVENTOR. fine-'2 h.Hnu/ 6 v WRNEYSH Patented Sept. 30, 1941 APPARATUS FOR MAKING CELLULARGLASS BLOCKS Elmer H. Haux, Tarentum, Pa., assignor to Pittsburgh PlateGlass Company, Allegheny County, Pa., a corporation of PennsylvaniaApplication January 2a, 1938, Serial No. 187,456

gas entrapped in the softened glass expands producing a cellular mass.When this operation is carried on in a mold and the content is suitablysolidified and annealed, a block is produced of low apparent density dueto its cellular composition and well suited for insulation in buildingconstruction. The present invention has to do with the production ofblocks of the character specified in a cheap, efficient manner suitablefor a commercial operation.

Briefly stated, the apparatus comprises a tunnel kiln through whichthemolds containing the mixture of glass and gassing material arecarried so as to secure in transit the necessary heating, cooling andanneal the molds being of knock-down form to permit the removal of theblocks, which have a tendency to stick in the molds.

As the blocks are often of considerable thickness, a long cooling andannealing period is required and.one of the objects of the invention isthe provision of a method of operation and apparatus whereby this periodmay be reduced to a minimum.

A difliculty encountered in the production of the blocks in molds is thetendency of the upper surfaces of the blocks to form a crust whichcracks open when the material expands. One object of the presentinvention is to overcome this diiiiculty, and this is accomplished, asmore fully described later, by the use of a top plate fitting into themold and free to move vertically when engaged by the top surface of theexpanding mass of glass, such plate permitting the expansion ofthegIa-ss, while servingv to prevent the crust formation and subsequentcracking be- :ildesl.K insuring a flat surface at the-top of the whenmetal molds of heat resisting composition are employed, difliculty isencountered after the glass has solidified due to the high coeflicienting a section in the tunnel x1111 immediately :01-

lowing the heating section which is open to the atmosphere and atwhichpoint the sides and cover plates of the molds are removed before theglass has dropped in temperature much beyond the solidification point.This avoids breakage in the subsequent cooling of the blocks to a pointonly slightly above the upper limit of the critical annealing range. Theblocks on their bottom plates are then carried through the annealingsection of the kiln where cooling occurs gradually through the criticalannealing range (about .1050 to 950 deg. F.). This open air exposurebefore annealing is of value in reducing the time of the operation eventhough the molds are of the non-metallic type (fused silica) which havelow expansion and therefore, would not have to be removed from theblocks as in the case of the metal molds.

Other objects of the invention are the provi- 2 0 sion of improved meansfor removing the molds from the blocks, and returning them to theentrance end of the kiln and the provision of a kilnof compact andefiicient construction in which a part of the heat from the heatingsection is uti- 25 lized in the annealing section.

Certain embodiments of the apparatus employed are illustrated in theaccompanying drawings, wherein:

Figure 1 is a plan view of one form of the apparatus. Fig. 2 is asection on the line II-II.

of Fig. 1. Fig. 3 is a perspective view of one form of the mold employedand certain cooperating parts. Fig. 4 is an enlarged side elevationpartially in section of the apparatus for re- 35 moving the molds fromthe blocks after they 40 control employed with the apparatus of Fig. 6.

And Fig. 8 is a perspective view of a modified mold construction.

Referring to the general arrangement of the apparatus as shown in Figs.1 and 2 of the drawings, the tunnel kiln here employed for handling themolds is made in two sections 9 and I0 arranged one above the other withan interposed wall II. kiln sections by means of the roller runwayscomprising the sets of suitably cooled rolls I2 and I3 driven as laterdescribed, so that molds in the upper section 9 are moved from the lefthand end of the kiln to the right hand end, and those in the lowersection are moved from the right hand end to the left hand end, whichThe molds A are carried through the movements are indicated by thearrows in Fig. 2. Transfer tables l4 and I5 are provided at each end ofthe kiln, such tables being carried upon plungers l6 working in thehydraulic cylinders ll. The molds are filled at the left hand end of thekiln while positioned on the table M, as shown, and are then carriedthrough the section 9 of the kiln to-the table I5. Here the cover platesand sides of the molds are stripped from the blocks and the table I5 islowered so that its runway is in line with the runway of the lower leersection, after which the blocks which have been formed in the molds arecarried to the left through the section III supported upon the bottomplates. Arriving at the left hand end of the kiln, these blocks passonto the table M, which is now in lowered position and run thereoveronto the receiving table I8 which is provided with rollers l9 forming arunway.

The mixture of powdered glass and gassing material, such as calciumcarbonate is fed to the molds while supported on the table M, asindicated in Fig. 2. The feeder includes the hopper 20, to which themixed batch is supplied from the chute 2|." This hopper 28 is preferablyprovided with a vibrating feeder 22, which delivers the material into atilting weigh hopper 23, just sufiicient material being supplied to thishopper to charge one of the molds. The weigh hopper discharges into@third hopper 24, which is also provided with a vibrator and dischargesthrough the flexible pipe 25 to the mold, such flexible pipe being :heldin inoperative position by means of the cable 26 provided with theweight 21 arranged as-shown.

The table l4 is' provided with a roller runway comprising the rolls 21a.driven through suitable reduction gearing from the electric motor 28carried upon the, table. The rolls are provided with spur gears upontheir ends which mesh with idlers 29 so that the drive of one roll fromthe right hand end of the table gives the proper rotation to all of therolls. The rolls 12 of the kiln section 9 are also driven from the motor28 when the table is in its upper position, as shown. At this time,agear on the end roll of the set 21a driven from the motor 28 engagesanidler meshing with a spur gear 29a (Fig. 1) on the end roll of theseries of rolls l2. The other end of this roll is provided with asprocket, and a chain 30 passing around this sprocket and over similarsprockets on the ends of the rolls [2 provides a drive for all of therolls to secure the movement of the molds through the kiln'section. Whenthe table I4 is in its lower position, it is arranged, as abovedescribed,,to drive the rolls. l3 of the lower kiln section III. Thetable I5 at the right hand end of the kiln sections has a driving meansincluding a motor 3| similar to that described] in connection with thetable Hi. When this table is in upper position, this motor drives all ofthe rolls of the upper kiln section 9, and when in lower position, itdrives all of the rolls of the lower,

kiln section. Provision is thus made for driving the transfer rolls inthe kiln sections from each end, and the motors are of the reversingtype, so that when the tables are in lower position, the reversed drivethereof rotates the rolls so as to carry the blocks in the lower sectionto the left. It will be understood in this connection that any suitablemeans might be employed for driving the rolls on the transfer tables andthe rolls in the kiln sections so as to give the proper movement of themolds and blocks through the sections.

The heating section 9 of the kiln is provided at its central portionwith a series of gas burners 32 which bring the temperature of thisportion of the kiln up to 1500 to 1750 deg. F., depending upon thecharacter of the charge in the molds; and the length of the heatingOperation in order to sinter the mass in the mold and permit it toexpand into a cellular mass, as heretofore described, will range fromone to three hours depending upon the character of the charge and thesize of the articles produced. The portions B and C of the heatingsection of the kiln are at a lower temperature than the central portionwhich is provided with the burners, so that a soaking action occurs inthe portion B and a cooling action in the portion C. The movementthrough this heating section of the leer is preferably an intermittentone, as otherwise, the section would have to be made of much greaterlength. Such movement may be obtained by alternately starting andstopping rollers l2, by appropriate control of the power, e. g. byturning the current on or off from .the actuating motors. The materialin the molds, while in the hot central portion of the heating section,is brought to a semi-fused, dough-like consistency which is necessary inorder to give the desired cellular structure. In th section C, the

mass in the mold cools sufliciently to form a solid block, but the blockis still at a temperature not greatly below the softening point of glasswhen the molds are run out onto the table I5. In orderto avoid heatlosses and maintain the kiln sections at proper temperature, suitabledoors 33 are provided at each end of each section, such doors beingoperated from the air cylinders 34.

The molds have a tendency to stick to the glass blocks formed therein,and in order to reduce this sticking to a .minimum, the interior of themold is coated with sand, chalk or the like, the use of sand beingpreferred. Such sand is applied mixed with water by spraying or paintingand allowed to'dry. When a metal bottom plate is employed in a mold, itis desirable to have a coating of sand or similar refractory material ofsubstantial thickness (preferably about onefourth inch) in order toprevent localized heating and blistering which will otherwise occur.Fig. 3 iilustrates a mold of the metal type consisting of the four sidewalls 35 of heat resisting steel welded together at their meeting ends,the bottom plate 36 of cast iron and the cover plate 31 preferably ofthe same composition as the sides. A suitable heat resisting compositionfor the sides and cover plate consists of a composition of 22 to 26 percent of chromium, 11 to 13 per cent of nickel, and

the balance iron. The cover plate has welded to its upper sides a pairof lugs 38 carrying latch members 39 journaled therein, members 39 whenpositioned, as indicated in full lines in Fig. 3, sup- 'port the coverplate at apos ition well above the mixture of powdered glass and gassingmaterial in the mold. -When these latches are turned through the angleof degrees, as indicated in dotted. lines, they act as a meanmwherebythe cover plate may be lifted from the mold when such mold is strippedfrom the block, as later described. The cover plate whensupported uponthe members 39 is free to move upwardly with respect to the sides of themold. It is spaced above the mixture in the mold at such a distance thatwhen the mass becomes viscous and expands to approximately thepredetermined thickness of the block to be produced, it engages theplate, which thus presses yieldingly upon the upper surface of the massby virtue of its weight. The plate might be weighted to give someadditional pressure, but a cover plate of about inch in thicknessprovides about the right amount of pressure upon the mass of material inthe mold. The use of this cover plate is important. Without such coverplate, the top surface of the mass of glass bulges and becomes crustedover in such manner that cracks occur. The use of the cover platesprevents this crusting over and flattens out the top surface of theblock, so that no finishing operation is required upon such surface. .Itis possible to operate without the use of the members 39 holding thecover plate spaced away from the mixture in the mold and allow the plateto rest directly upon the mixture from the beginning and rise therewithas it expands. Difiiculty is encountered, however, under these conditiondue to the tendency of the cover plate to tilt and wedge. It also has atendency to lie at an angle tothe horizontal, after it has completed itsupwardmovement, even though it does not wedge during such movement.

The table I5 at the right hand end of the kiln sections constitutes acooling station for giving a rapid drop in temperature in the blockintermediate its transfer from the heating section 9 to the annealingsection Hi. This rapid cooling in the open air is desirable, as it cutsdown the time which the mold and block would otherwise have to remain inthe kiln. The block and mold may have a temperature as high as 1450 deg.F. when taken onto the table l5. While on such table, the sides and topplate of the mold are removed, so that it is exposed to cooling on thebottom plate 36. Under these conditions, a very rapid cooling occursbefore the block on its plate is transferred to the annealing sectionID. This drop in temperature may be to any point above the upper limitof the critical annealing range, such upper limit being about 1050-deg.F. As long as the drop in temperature in the open is not below thispoint, no damaging to the block occurs. The temperature in the annealingsection Il covers the critical annealing range from 1050 F. or slightlyabove to a point'below 950 deg. As the blocks are carried through theannealing section from right to left, they drop through this rangegradually and arrive at the left hand end of the kiln at a temperaturesuitable for removal on the table l4. The placing of the two sectionsone above the other gives a compact arrangement and reduces heat losses.An opening Ha (Fig. 2) in the wall II permits of a heat transfer fromthe upper to the lower section.

The apparatus for stripping the molds from the blocks will be seen byreference to Figs. 4 and 5. A carrier 40 provided with the wheels 4| ismounted on an overhead mono-rail 42 which extends transversely of thetable l5. This support includes a pair of cylinders 43, 43a, in whichare mounted the plungers 44 and 45. The plunger 44 carries a plate 45 atits lower end which is adapted to engage the top plate 31 of the moldand hold the plate down while the sides 35 are being stripped upward.The plunger 45 carries a transverse arm 41 provided with depending hooks4a which are adapted to hook under the brackets 49 secured to the moldsides. Air is supplied to the two ends of the cylinder 43 by means ofthe connections 50 and 5| leading to the air supply pipe 54"andcontrolled by a four-way valve 55. Air is supplied and released from thecylinder 43;: by the connection 55 provided with the three-way valve 51.

the mm, as indicated in Fig. 4 and air is 'admitted above the plunger 44and below the plunger 45, the. latch members 39 being at this timeturned to their dotted line positions (Fig. 3). The block 58 is thusheld down against its bottom plate by the plate 46 and at the same timethe hooks 48 are moved upward by the plunger 45, thus stripping thesides of the mold from the block. With the members 39 turned to theirdotted line position, as indicated in Fig. 3, both the sides of the moldand the top plate are now carried upon the trolley device on themonorail- 42. This mono-rail 42 leads back to the entrance end of thekiln, as indicated in Fig. 1, so that a convenient means is thusprovided for transporting the mold parts back to the entrance end of theleer for reuse.

Fig. 8 illustrates a diiferent type of mold which may be used in placeof the metal mold heretofore described. The parts of this mold are.

preferably made of fused silica mixed with an aluminous cement. which isrelatively strong and which has a very low coefficient of expansion. Inthis construction, the four side walls 59 are separate from each otherand rest removably upon the bottom plate 60 of fused silica. The bottomplate and side walls are held in assembled relation by means of cornerbrackets 6| having pins 62 adapted to engage perforations 63 in thebottom plate, thus providing adjustment for supporting side walls ofdifferent dimensions upon the same bottom plate. cover plate, in thiscase fused silica composition, is employed, such plate resting on theside walls 59 and free to move vertically. This type of mold has lesstendency to stick to the glass block and involves no requirement forstripping the mold from the block after the block has solidified. Thesilica composition has a slightly lower coefiicient of expansion thanthe glass, so that a the' block may be completely cooled down in the Inoperation the stripping device is applied to F5 mold without injury tothe mold or to the block itself. However, if desired, and in order tospeed up the operation, the sides and cover plate of the'mold may beremoved, as heretofore described, in an open section of the kiln, inorder to provide more rapid cooling and annealing.

Fig. 6 illustrates a modified kiln arrangement, in which the heating andannealing sections are all on the same level, instead of being on twolevels as in the construction of Figs. 1 and 2. In this construction, 54is a section in which the molds are preheated preliminary to filling; 65is a feed device for filling the molds; 66 is the heating section, inwhich the same function is accomplished as in the section 9 of the firstconstruction; and 51 is an annealing section. Be

tween the heating and annealing section is an open air station, as inthe first construction, such station being utilized for stripping themolds by the use of a mechanism 68, such as that shown in Fig. 4. Theoperation is in substance the same as that heretofore described, themolds being moved upon the roller runway 69 in an intermittent manner,so as to permit the use of a shorter kiln than would otherwise berequired. The open air station is not only utilized to strip the molds,but permits of quick cooling preliminary to annealing, thus shorteningthe time period required, as heretofore pointed out in connection withthe first type of construction. 1

Fig. '7 illustrates an automatic feeder which may be used with the typeof construction shown This gives a composition As in the other type ofconstruction, a

in Fig. 6, wherein the molds are carried one after the other beneath thefeeding device. This feeding device comprises the hopper I and a tableII which is vibrated electrically to feed a mixture of the glass andgassing material downward through the chute I2. Automatic means areprovided for stopping the. vibration of the chute during the period inwhich the molds are not in proper position-beneath the line of feed fromthe chute. The means for doing this will be apparent from the wiringdiagram, wherein I3 is the coil of the vibrator and I4 is a relay coilwhich operates the switch I5. The molds are arranged so that they engagethe rollers on the ends of the switch arms I6 and II, which make andbreak contact at I8 and I9. When the mold is out of contact with theroller on either of these arms, the circuit is broken in such mannerthat the vibrator operated by the coil I3 ceases to function. This willbe apparent from a consideration of the diagram of Fig. 7, assuming thatthe molds are moving from left to right, as indicated by the arrow. Thecontacts at It and I9 are now closed and current flows from the lead 80to the lead 8| through the coil M via the connections 82, 83 and 84.This causes a closing of the switch arm I5, so that current flow occursthrough the coil I3 via the lead 80, arm I5, wire 85 and wire 86. Themachine. therefore, feeds until the roller on the arm 'II passes off ofthe left'hand end of the mold, breaking the contact at I9 andinterrupting the circuit through the coil I4 so that the switch opensand the circuit through the coil I3 is interrupted. When the roll on thearm I6 passes oil of a mold, the contact at 18 is also broken.

It is now necessary to make both of these contacts at I9 and I8 beforethe feed will start again, and this will not occur until the next moldmoves the arms I6 and II to operative position again, as shown in Fig.7.

What I claim is:

1. In apparatus for making a cellular glass block from a mixture ofcrushed glass and a gassing material, a mold comprising a bottom plate,vertical sides mounted removably on the bottom plate, and a cover platefitting inside said sides and free to move vertically, and means forstripping the sides from the block formed by the solidification of themold content, and

for removing the sides and top plate to a point remote from the bottomplate and the block, comprising an overhead carrier mounted upon asupport comprising means permitting horizontal movement of the carrier,means on the carthe cover plate, and means on the carrier for giving thepresser means its vertical movements.

2. Apparatus for making cellular glass blocks, said apparatus comprisingmolds for a mixture of crushed glass and a gassing material, means tocharge the molds with such material, a tunnel kilnadjacent the lattermeans, devices in the kiln to heat the material in the molds to thesintering temperature of the glass, conveyor ele-' ments for moving themolds through the tunnel kiln while the material is being heated,a'second,

tunnel kiln having its inlet end adjacent to the discharge end of thefirst-mentioned tunnel kiln, a conveyor for conducting blocks throughthe second tunnel kiln for annealing the blocks, means atthe dischargeend of the first tunnel kiln for stripping the molds from the blocks andmeans to transfer the stripped blocks to the second tunnel kiln.

ELMER H. HAUX.

